Electrical relay



June 6, 1950 A. H. LAMB 2,510,700

ELECTRICAL RELAY Filed July 6, 1945 Patented June 6, 1950 ELECTRICAL RELAY Anthony H. Lamb, Hillside, N. J., assignor to Weston Electrical Instrument Corporation, Newark, N. J a corporation of New Jersey Application July 6, 1945, Serial No. 603,425

7 Claims. 1

This invention relates to electrical relays and particularly to novel mechanical constructions for small auxiliary relays such as commonly termed power relays" in the instrument relay control art.

There are limits to the electrical loads that may be directly controlled by the contacts of sensitive instrument type relays, and one or more auxiliary or power relays may be connected between the instrument type relay and the load circuit when the latter is of such character that the contacts of the instrument type relay would be badly pitted and/or welded to each other if connected directly into the load circuit to open and close the same. The power relays have been of the pivoted armature type, with the moving contact carried by or actuated by the armature. The accumulations of dust and lint in the armature bearings have been the most general source of difllculty with prior power relays, and some special uses have their own problems such as, for example, difilculties from the freezing of moisture on the hinge or bearings in the case of relays on high altitude aircraft. The design and adjustment of prior power relays have been rather critical as the safety factor for insuring reliable operation has been only about 25%, i. e. the relay may fail to operate if the source voltage drops 25% below normal.

Objects of the present invention are to provide relays that substantially completely eliminate all diiliculties from dust, lint, moisture and corrosive vapors, and that function satisfactorily over a wide range of subnormal source voltages. b- Jects are to provide relays of small size and simple design that have no bearings and hinge pins, the

moving contact or contacts being free-floating on Fig. 2 is a similar view showing the relay mounted on a panel, and with some parts in section;

Figs. 3 and 4 are end elevations as seen from the left and the right, respectively, of Fig. 1;

Fig. 5 is a side elevation of another embodiment, with the primary control circuit and the load circuit shown diagrammatically;

Fig. 8 is a front elevation of the relay of Fig. 5;

Fig. 7 is a side elevation of a double contact relay embodying the invention; and

Fig. 8 is a side elevation of another embodiment.

In the several views of the drawings, the reference numeral I identifies a coil or winding having terminal lugs I, the coil being of annular cross-section and provided with a cylindrical core of soft iron 2 that constitutes one contact element of the relay. The outer or contact end of the core 2 is provided with a thin layer 3 of a noble metal or an alloy of good contact characteristics. the layer 3 being applied directly to the core 2 or, preferably, being a coating on a contact plug or rivet 4 having a stem that is force-fitted into an axial bore of the core 2. The coil I may be wound upon the core 2 or may be separately wound and cemented to the core. A terminal lug 5 is secured to the core 2 by a screw 6 and, in some embodiments of the invention, the screw 6 may constitute the means for securing the relay to a panel I, see Fig. 2.

Referring particularly to Figs. 1 to 4 inclusive, the coil I and core 2 are mounted within a U-shaped bracket or yoke 8 of iron to which they may be cemented or may be held by a clamping action when the plate or cross-bar 9 of insulating material is secured between the ends 01 the yoke 8 by screws III. The movable contact of the relay is a. soft iron button I I having a spherical or'otherwise rounded surface opposed to the core or stationary contact 2, the. button II having a cover layer, not separately shown, of a noble metal or good contact ,alloy. The movable contact II is floated in spaced relation to the core 2 by a coiled or helical spring I2 that has one end welded or brazed to the contact II, the other end of the spring being threaded upon a supporting screw I3 that is threaded through the insulating plate 9. A terminal lug I4 is secured to the screw I3 by a nut I5 that has the additional function of a locknut to prevent inadvertent rotation 01 the screw I 3.

The efiective resiliency oi the spring I2 may be adjusted by threading it to a greater or less extent upon the screw I3, and the spacing oi. the contact II from the .core 2 may be adjusted in the same manner or, alternatively, by turning the supporting screw I3 in the insulating plate 9.

The free floating of the'movable' contact has a, number of advantages in addition 'to' those that result from the elimination of a hinge or pivotal support. Stable operation under relatively high vibration is'obtained, and reliable contact closures result from the floating support and the rounded surface or the contact II. The rounded energization of the coil I.

contact button II will rock or roll upon the end surface of the core 2 as it seeks to reduce the 'netic material. Another and an important ad-- vantage of the invention arises from the fact that successive contactengagements do not take place at the same pointson the core 2 andcontact button I I. The contact points retain minute magnetic charges or the same sign when the contacts separate, and these charges tend to prevent an engagement of the same points upon the next The invention is not limited to any particular size but it does permit or small compact constructions that are or special advantage when the available space is limited. The relays as manuractu'red and used have been quite small,v and 2 Figs. 1 to 4inclusive are on an enlarged scale.

As shown in Figs. 5 and 6, the yoke 8' may be I of shallow U-form with one arm supporting the coil I and core 2, 'and'the other arm provided with an insulating bushing 9' for the screw I3 to which the contact I I is connected by a helical spring I2. The yoke or bracket 0' has openings I6 for receiving screws, not shown, for securing the relay to a panel or other support. The circuit connections shown in Fig. 5 v are conventional, i. e. a current source .S is connected in series circuit with the terminals I' or the power relaycoil I through the contacts of an-instrument type relay I, and the load I'l and-a current source S are connected in series between the terminal ing 5 or the core 2 and the terminal lug I4 of the movable contact II.

As shown in Fig.7, a coil I and its core 2 may be supported on a yoke or rectangular frame I8 d by angle brackets 19 that have an arm apertured 40 to fit over the core '2 and a base apertured to receive screws 20 that clamp, the brackets to the yoke I8. Movable contacts II are floated adiacent the opposite ends 01 the core 2 on springs 7 I? t, as Previously d s ri ed. are threaded axially from said core, and means including a upon screws I3 that extend through and 'are in-- sulated from the yoke I8 by insulating bushings 9'. The axes of the springs I2 are normal to the 'core axis in the illustrated relay but it will be ap- Iclaim:

1. A power relay for energization by a sensitive instrument type relay; said power relay comprising a coil on a cylindrical core or magnetic material, a contact secured to one end of said core, a bracket and means securing the coil and core thereto, a movable contact button of masnetic material having a rounded surface opposed to said contact on the core, and means supporting said movable contact on said frame for relative rolling movement of the rounded contact button upon said core contact when the coil' is energized; said supporting means comprising a screw support secured to said bracket, a screw threaded through said screw support, and a hellcal spring having one end adiustably threaded upon said screw, the contact button being secured to the other end of said helical spring;

whereby the effective resiliency of the spring may be adjusted by threading the same to a greater or less extent upon said screw, and the normal spacingot the contact button from the core contact for any given eilective resiliency oi the spring may be adjusted by turning said screw in said screw support.

2. A power relay as recited in claim 1, wherein the axis of said screw and helical spring substantially coincides with the axis or said cylindrical core.

3. A power relay as recited in claim 1, wherein said bracket is of iron and constitutes a magnetic yoke for said cell and core.

4. A power relay as recited in claim 3, wherein said bracket is of U--shape, and said screw support comprises a plate of insulating material secured between the ends of said U-shaped. bracket.

5. A power relay as recited in claim 3, wherein said bracket isof U-shape, and said screw support comprises a bushing of insulating material set into one arm of the U-shaped bracket.

6. A relay comprising a coilon a core 01 magnetic material, a bracket and means mountin said core and coil on said bracket, a contact of magnetic material at each end of and spaced helical spring supporting each contact from said bracket and insulating the same from said core; said supporting means including insulating bushings set in said bracket, and screws adiustably parent that the coaxial arrangemen f Fi 1 I threaded into said bushings; said helical springs to 6 could be employed. The core 2 may be insulated from the brackets I9, or the brackets may be of insulating material when it is necessary or desirable to .isolate the yoke or bracket I3 from the load circuit.

In another embodiment of the invention, as

' shown in Fig. 8, the movable contact II isnormally supported in spaced relation to the contact surface 3 or core '2 by a coiled spring 2| that extends at right angles to the path or movement 00 of the contact II. The coil I and core 2 are se-- cured to a base or mounting strap 22 by a screw being adjustably threaded upon said screws to determine the effective resilience thereof.

7. A relay as recited in claim 6, wherein said supporting means for each contact includes 56 means mounting the spring of that contact on the bracket'with its axis normal to the axisof said core.

ANTHONY H. LAMB.

7 REFERENCES orrnn The following references are of record in the ,file of this patent:

UNITED STATES PATENTS 08 Number Name Date 848,148 Woerhle Mar. 26,1907 978,999 Gemsback Dec. 20,1910 1,574,513 ,7 Ratlifi et al Feb. 23, 1926 1,722,186 Vincent July 23, 1929 I0 2,059,702 Matthias Nov. 3, 1936 Manley Aug. 23, 1938 

